The aim of this clinical study is to assess the long-term efficacy and safety of BCD-132 (divozilimab) in patients with multiple sclerosis who previously participaded in BCD-132-2 and BCD-132-4/MIRANTIBUS studies

Clinical study BCD-132-EXT is a Phase III study extension conducted after completion of BCD-132 500 mg therapy by subjects of clinical studies BCD-132-2 and BCD-132-4/MIRANTIBUS.

The study is designed as a multicenter, open-label, non-randomized, non-comparative, single-arm clinical study.

The study consists of a screening period (14 days), a treatment period (96 weeks) and a follow-up period (4 weeks). During treatment period, the subjects will receive the investigational product BCD-132 (divozilimab).

The duration of participation for each subject will be approximately 102 weeks.

Inclusion Criteria:

• Written informed consent of the subject to participate in the study has been obtained.
• The subject was in the BCD-132 500 mg group in BCD-132-2, then transferred to BCD-132-4/MIRANTIBUS and completed it according to the Protocol (completed all scheduled study visits).
• Last administration of BCD-132 in BCD-132-4/MIRANTIBUS was performed at least 22 weeks before the planned date of the first drug administration in this clinical study.

Exclusion Criteria:

• Heart failure (NYHA class III/IV).
• Malignancies detected after completion of study BCD-132-4/MIRANTIBUS and prior to signing the informed consent to participate in this study, as well as conditions (acute and chronic) precluding further treatment and participation in the study in the Investigator's opinion.
• Metabolic abnormalities according to blood chemistry (including increased creatinine, urea, ALT, AST) and/or blood count abnormalities (including decreased white blood cell count, absolute lymphocyte count, absolute neutrophil count, platelet count, decreased hemoglobin concentration) identified at the screening and precluding further treatment and participation in the study in the Investigator's opinion.
• Pregnancy, breastfeeding, or planned pregnancy at any time during the participation in the study and 48 weeks after the scheduled last administration of the product in this study.
• Use, between the completion of participation in BCD-132-4/MIRANTIBUS and the signing of the informed consent for this study, of the following drugs: anti-B cell therapies (e.g., rituximab, ocrelizumab, abatacept, belimumab, ofatumumab, and others); alemtuzumab, daclizumab, teriflunomide, mitoxantrone, cladribine; cyclophosphamide, cyclosporine, azathioprine; mycophenolate mofetil, fingolimod and other sphingosine-1-phosphate (S1P) receptor modulators, natalizumab.
• Known intolerance, including hypersensitivity to any component of BCD-132, premedication drugs, or conditions in which the above drugs are contraindicated in the Investigator's opinion.
• Historical evidence of progressive multifocal leukoencephalopathy (PML).
• Contraindications to MRI and the use of gadolinium-containing contrast agents, including, but not limited to, the presence of metal foreign bodies, artificial heart valves, electronic middle ear implants, pacemakers; allergies to gadolinium or gadolinium-containing contrast agents.